[2][3] Tilia johnsoni leaf fossils have been identified from two locations in the Eocene Okanagan Highlands, the Klondike Mountain Formation near Republic, Washington and at the Quilchena locality near Merritt, British Columbia.

[5] The Quilchena locality is dated to 51.5 ± 0.4 million years ago , and is reconstructed as the warmest and wettest of the Early Eocene upland sites from the Okanagan Highlands of British Columbia and northern Washington State.

Working from this specimen, collected in the Republic, Washington area in the early 1980s, the fossil was studied by Jack A. Wolfe of the University of California and Wesley C. Wehr of the Burke Museum.

[1] They published their 1987 type description for the species in a United States Geological Survey monograph on the North Eastern Washington dicot fossils.

The specific epithet johnsoni is a patronym recognizing the help provided to Wolfe and Wehr by a young Kirk Johnson, now director of the Smithsonian's National Museum of Natural History.

The highlands likely had a mesic upper microthermal to lower mesothermal climate, in which winter temperatures rarely dropped low enough for snow, and which were seasonably equitable.